A corner of a classroom is formed by two walls and the floor, which are mutually perpendicular. Let the corner be point $O$. There is a triangular baffle $A B C$ with vertices $A , B , C$ located on the intersection lines between walls or between walls and the floor, at distances of 20, 20, and 10 centimeters from corner $O$ respectively. The three sides $\overline { A B }$ , $\overline { B C }$ , $\overline { C A }$ are flush with the walls or floor, as shown in the figure. Find the area of the triangular baffle $ABC$.
A corner of a classroom is formed by two walls and the floor, which are mutually perpendicular. Let the corner be point $O$. There is a triangular baffle $A B C$ with vertices $A , B , C$ located on the intersection lines between walls or between walls and the floor, at distances of 20, 20, and 10 centimeters from corner $O$ respectively. The three sides $\overline { A B }$ , $\overline { B C }$ , $\overline { C A }$ are flush with the walls or floor, as shown in the figure. Find the area of the triangular baffle $ABC$.